This article has been reviewed according to Science X's editorial process and policies. Editors have highlighted the following attributes while ensuring the content's credibility: In March 2026, scientists succeeded in transporting antiprotons by road for the first time in a purpose-built trap loaded on a truck. The BASE collaboration, which realized this experiment at the European Organization for Nuclear Research (CERN) in Geneva under the lead of Professor Dr Stefan Ulmer and Dr Christian Smorra from Heinrich Heine University Düsseldorf (HHU), now presents its findings and experiences from this pioneering experiment in the journal Nature.
Among other things, they report that it was possible to store antiprotons in a mobile transport vessel for more than a month for the first time ever. Comparing protons—the positively charged components of an atomic nucleus—with antiprotons—their antimatter counterparts—is one of the most promising methods for seeking differences between matter and antimatter. Any identified difference in their mass or magnetic moment could point to the potential origin of the matter-antimatter asymmetry that can be observed in the cosmos.
So-called ultra-high-vacuum Penning traps enable high-precision measurements of the protons and antiprotons confined in them. The BASE (Baryon Antibaryon Symmetry Experiment) research collaboration designed and now operates a trap of this kind—known as BASE-STEP—at CERN, or more precisely, the "Antimatter Factory" (AMF) there. The AMF is the only facility worldwide where low-energy antiprotons can be produced, stored and studied.
Professor Ulmer, holder of the Chair of Quantum Technologies and Fundamental Symmetries at HHU, and the founder and spokesperson of BASE and coauthor of the new study, states, "In recent years, we have already achieved precision measurements of the intrinsic magnetic moment of both types of particles with an accuracy of 0.3 ppb for protons and 1.6 ppb for antiprotons." The abbreviation ppb stands for parts per billion and equates to 1 × 10-9. To date, however, comparisons of the data obtained on protons and antiprotons have not identified any difference within the achievable measurement accuracy. Smorra, BASE-STEP principal investigator and corresponding author of the study, said, "We cannot further improve measurement accuracy at the AMF because facility operation causes magnetic-field fluctuations, which affect our measuring equipment.
We can only find better conditions outside CERN. And so the idea of the mobile, open BASE-STEP trap was born: We will transport the antiprotons to another location with a high-precision laboratory to achieve at least a 100-fold improvement in precision." Following the success of the proton transport in October 2024, the BASE team succeeded in using the same trap to transport antiprotons in March 2026. A total of 92 particles were extracted from the AMF and stored in BASE-STEP.
The trap was then loaded onto a truck and driven around the CERN site for half an hour, covering a distance of about 8 kilometers (5 miles). The team then succeeded in unloading the trap without losing any of the stored antiprotons. Marcel Leonhardt, a doctoral researcher in physics at HHU and lead author of the study, said, "We then continued to observe the antiprotons.
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